"Aaron Werman" <awerman2(at)hotmail(dot)com> writes:
> I imagine a design where a shared plan cache would consist of the plans,
> indexed by a statement hash and again by dependant objects. A statement to
> be planned would be hashed and matched to the cache. DDL would need to
> synchronously destroy all dependant plans. If each plan maintains a validity
^^^^^^^^^^^^^
> flag, changing the cache wouldn't have to block so I don't see where there
^^^^^^^^^^^^^^^^^^^^^^
> would be contention.
You have contention to access a shared data structure *at all* -- for
instance readers must lock out writers. Or didn't you notice the self-
contradictions in what you just said?
Our current scalability problems dictate reducing such contention, not
adding whole new sources of it.
regards, tom lane